This invention relates to metal catalyst supports. Such supports comprise metal "skeletons" which are coated with catalyst, and through which gas flows. The catalyst support must allow the catalyst to contact the gas without impeding the flow of gas. Examples of such supports are given in my prior U.S. Pat. Nos. 4,162,993, 4,190,559, and 4,301,039, the disclosures of which are incorporated by reference herein.
If one must treat catalytically the flue gas from an electric power plant, the flow of gas is enormous, and so is the cross sectional area of the catalyst. The preferred shape of the catalyst support for treating flue gas is a rectangle. Individual rectangles can be nested together like panes in a window, to fill a large cross section. U.S. Pat. No. 4,190,559 describes a method of stacking separate strips to form rectangular catalyst supports. In the present invention the rectangles are formed by folding a single strip of metal upon itself. This gives a more rigid honeycomb.